Approximately one third of all deaths in the affluent society of the western world result from coronary artery disease, and almost all elderly persons have at least some impairment of the coronary artery circulation. For this reason, the normal and pathological physiology of the coronary circulation is one of the most important subjects in the entire field of medicine.
One way of treating coronary artery disease is by coronary artery bypass grafting, which is surgery where vessel grafts are used to bypass one or more stenoses (constrictions) in the coronary arteries.
The success of a bypass grafting surgery operation depends on several factors, including the quality of the graft(s), the position of the graft(s) and methods for assessing the quality of a graft and methods for assessing the possible contribution of a graft to the arterial blood supply of the myocardium.
Most current methods for increasing the benefits of a bypass grafting surgery operation are of manual nature, relying on skill and experience of the surgeon. There seems to be few methods and devices for assessing the absolute quality of a graft and related matters in an objective and numerically presentable manner.
Thus, there is a need for a method and a device for assessing graft quality, making it possible to further increase beneficial outcome of coronary artery bypass grafting surgery.
Descriptions of coronary anatomy can be found in a textbook or atlas, e.g. Arthur C Guyton 1991, Textbook of medical physiology, eight edition, W.B. Saunders Company, Harcourt Bruce Jovanich Inc., London, page 234-244.
Background of certain medical terms used in this document can be found in the following articles: “Competitive flow”, A technique for evaluating competitive flow for intraoperative decision making in coronary artery surgery, Gil Bolotin et al, Ann Thorac Surg 2003; 76:2118-2120; Does competitive flow reduce internal thoracic artery graft patency?, Sabik J F 3rd et al., Ann Thorac Surg 2003 November; 76(5):1490-7; “Run off quality”, Prospective evaluation of coronary arteries: influence on operative risk in coronary artery surgery, H. Corbineau et al, Eur J Cardiothorac Surg 199; 16:429-434; “Flow resistance”, Intraoperative assessment of coronary flow and coronary vascular resistance during coronary bypass surgery, Scan Cardiovasc J. 199; 33(1):23-8.
Ischemic Heart Disease
Ischemic heart disease is a term for heart-related conditions caused by poor delivery of blood that carries oxygen to the heart. It is most commonly caused by blockages in the coronary arteries, the blood vessels that provide blood to the heart muscle itself. Ischemic heart disease is also known as coronary heart disease and coronary artery disease, and includes heart attack and angina (chest pain or discomfort). Heart disease usually develops over time as cholesterol and fat build up on the inside of the heart's arteries, narrowing the space through which blood flows. Chest pain or discomfort, also called angina, may occur when not enough blood reaches the heart. A heart attack occurs when a part of the heart dies because the blood supply was blocked and there was not enough oxygen to keep it alive.
Surgical Treatment of Coronary Disease
In many patients with coronary ischemia, the constricted areas of the coronary vessels are located at only a few discrete points, and the coronary vessels beyond these points are normal or almost normal. A surgical procedure has been developed in the past 25 years, called aortic coronary bypass (CABG), for anastomosing small vein grafts to the aorta and to the sides of the more peripheral coronary vessels. Usually, one to five such grafts are performed during the operation, each of which supplies a peripheral coronary artery beyond a block. The vein that is used for the graft is usually the long superficial saphenous vein removed from the leg of the patient. The acute results from this type of surgery have been especially good, causing this to be the most common cardiac operation performed. Anginal pain is relieved in most patients. Also in patients whose hearts have not become too severely damaged prior to the operation, the coronary bypass procedure often can provide the patient with normal survival expectation.